A technique that may improve the reliability of endobronchial blocker positioning during adult one-lung anaesthesia.
To improve the performance of EBs, our group proposed to deliberately pass the ETT tip distally to almost touch the carina and deflect the EB balloon sideways through the Murphy eye, and have used this technique on small children with apparent success (7). We have extended our ethically approved study of this technique to adults. We herein report variations of this technique in adults in whom there were important drawbacks associated with the DLT.
A 31-year-old woman was to undergo right video-assisted thorascocopic (VAT) thymectomy for severe myasthenia gravis. She had suffered from repeated respiratory failure, including an episode three weeks earlier. We planned postoperative ventilation in the intensive care unit. To avoid changing tubes at the end of surgery, we chose a 7.5 mm ID ETT and a 9 Fr Coopdech EB tube (Daiken Medical Co., Ltd, Osaka, Japan; the Coopdech is similar to the Arndt EB; the Coopdech ETT connector is similar to the Arndt multiport adaptor; its balloon is pre-bent slightly to one side to facilitate bronchial intubation and it does not have a wire loop like the Arndt). The EB was 'pre-inserted' into the ETT lumen via the Coopdech ETT connector before intubation (Figure 1); the EB balloon tip was made to emerge through the Murphy eye and the catheter was then locked at the proximal end with the blocker tube clamp (equivalent to the Tuohy-Borst type valve on the Arndt multiport adaptor).
[FIGURE 1 OMITTED]
[FIGURE 2 OMITTED]
During intubation, once the ETT tip had passed the larynx, the ETT-EB was turned such that the balloon faced the right. The ETT tip was placed close to the carina (Figures 2A, 3) by passing the ETT tip to a depth estimated to be at the carina (27 cm as measured at the upper incisors in this case). At this depth, before EB balloon inflation, bilateral breath sounds on auscultation, bilateral chest movement on inspection and low inflation pressures confirmed that the ETT tip was within the tracheal lumen. A further 1 cm distal advancement resulted in greatly diminished left lung ventilation, confirming endobronchial intubation. The ETT was then withdrawn slightly such that bilateral breath sounds and chest movement were evident again. The EB balloon was then advanced a further 2 cm so it would slide into the right mainstem bronchus. The locations of the ETT and EB balloon were confirmed fibreoptically before and after EB balloon inflation. Endobronchial balloon inflation to isolate the right lung was performed at the end of an expiratory pause of 10 seconds. The right lung was collapsed satisfactorily for two hours during the case. At the end of surgery, the EB was removed without difficulty and the ETT tip was withdrawn to mid-trachea.
[FIGURE 3 OMITTED]
A 16-year-old girl with double major scoliosis was to undergo right VAT T8-11 discectomies plus spinal fusion. Chest X-ray revealed gross spinal deformity and tracheal distortion. Wary of the rare occurrence of DLT-induced injuries (8-10), we decided to avoid negotiating a DLT through the distorted trachea. Instead, the technique chosen was identical to that described in Case 1, except that an Arndt 7 Fr EB and Multiport Adaptor were used with a 7 mm ID ETT. Lung collapse during the three-hour VAT surgery was excellent. Afterwards, the patient's ETT was exchanged for an armored ETT for posterior spinal fusion. The patient recovered uneventfully.
A 34-year-old man was scheduled for left VAT decortication. He had a history of myasthenia gravis and respiratory failure. Postoperative intensive care unit care was planned. A 9 mm ID ETT was inserted after induction of general anaesthesia. A 9 Fr Coopdech EB was introduced through the ETT lumen to emerge at the ETT tip (not through the Murphy eye) to block the left main bronchus under fibreoscopy. The ETT was rotated 180[degrees] so that the bevel faced the right and the ETT was advanced until its tip reached the carina (Figure 2B). The position of the EB and ETT were confirmed before the fibrescope was withdrawn and again after right lateral positioning. Surgery was completed with excellent lung collapse for three hours. The EB was then removed, ETT position readjusted and the patient was transferred.
A 57-year-old woman required a left VAT for lung tumour resection. Her laryngoscopic view was Cormack and Lehane grade 2b in spite of cricoid pressure, and initial attempts at intubation with an 8 mm ID ETT 'pre-loaded' with an intraluminal 9 Fr Coopdech catheter emerging through the Murphy eye failed. Given the poor laryngoscopic view, we opted to intubate with an 8 mm ETT formed into a hockey stick shape using a stylet, aided by posterior pressure on the larynx. Once through the larynx, the ETT was pushed distally until its tip reached the carina. It was then rotated 180[degrees] such that the bevel was facing the right bronchus and the Murphy eye, the left. Prior to insertion, the marking at the ETT connector of a Coopdech catheter when its tip reached the Murphy eye was noted using another 8 mm ID ETT. Then, with its bent blocker balloon tip angled towards the left, the deflated and lubricated Coopdech catheter was passed within the ETT lumen blindly and with little difficulty through the Murphy eye into the left mainstem bronchus (Figure 2C). A fibrescope was then used to verify the positions of the ETT and the balloon (Figure 4). Lung collapse lasted three hours and was excellent. The patient recovered uneventfully.
[FIGURE 4 OMITTED]
A 67-year-old, 86 kg, 172 cm man was to undergo mediastinoscopy for staging of lung cancer. The surgeons claimed that they were "almost certain" that lung resection would not be required. The anaesthetist intubated the patient's trachea with a standard 9 mm ETT. The mediastinal nodes turned out to be negative for cancer and the patient had to undergo VAT right upper lobectomy. Instead of changing to a DLT, we simply made sure that the ETT Murphy eye was facing the right, advanced the ETT to a depth just before loss of bilateral ventilation and then advanced blindly a 9 Fr Coopdech with its tip angling to the right until it emerged through the Murphy eye (a subtle resistance followed by a 'give' was felt). The final balloon positioning and inflation were confirmed with a fibrescope. The right main bronchus was rather short and some 20% of the EB had to be left above the carina. Lung isolation was nonetheless excellent and no EB displacement occurred. The 3.5 hour VAT surgery was uneventful.
We have described a technique that may reduce the chance of cephalad endobronchial balloon dislodgement into the trachea during adult OLA when a single-lumen ETT and a separate EB are used. This technique had been applied earlier in children too small to accommodate any DLT (7). The idea is to place the ETT tip near the carina to block the balloon's cephalad passage. Making the balloon emerge through the Murphy eye makes accidental blockade of the ETT tip even more unlikely. An added advantage of this arrangement is that the left/right orientation of the balloon can be changed by rotating the ETT. In fact, once the ETT tip had passed the larynx during intubation, we turned the unit such that the EB pointed to the side to be blocked, much like the situation with the DLT.
One drawback with this technique is that the EB and the Coopdech connector/Arndt adaptor must be attached to the ETT during intubation, making the task slightly cumbersome. The presence of an intraluminal EB catheter in the ETT precludes the use of a stylet or bougie in difficult intubations (Case 4). When that happens, we first intubate the trachea with an ETT of [greater than or equal to]8.5 mm ID without the EB; then pass the EB through the ETT lumen with the deflated balloon pointing towards the side to be blocked, thus allowing the balloon to emerge through the Murphy eye into the mainstem bronchus (Cases 4 and 5). We recommend that, when using this 'blind' technique, the operator has knowledge of the exact depth at which the tip of the Coopdech catheter is at the Murphy eye. The easiest way is to use another ETT of the same size and pass the Coopdech catheter within its lumen to simulate placement. In separate in vitro experiments, we showed that passing the EB through the Murphy eye was very easy with an ETT [greater than or equal to]8.5 mm ID, but moderately difficult with an ETT 8 mm (that notwithstanding, we were able to easily pass the EB balloon through the Murphy eye of an in situ ETT 8 mm ID in Case 4, almost as easily as with an ETT 9 mm ID in Case 5) and almost impossible with smaller ETTs. The Cohen Flexitip (Cook) EB has a 9 Fr catheter and with its directionally-adjustable tip, should also be suitable for this technique. Also, in vitro we were unable to snare an adult Arndt blocker through the Murphy eye with a fibrescope. The Arndt blocker is therefore not amenable to 'blind' passage through the Murphy eye, with or without fibreoptic guidance, unless it had been 'pre-loaded' before intubation. For intubations requiring a stylet or bougie, and for ETTs <8.5 mm ID, the configuration shown in Figure 2B is an option.
Another drawback is that with the ETT 'coaxially pre-loaded' with an EB, increased airway resistance, especially with smaller ETTs, is expected. The problem was not serious in any of our cases, but could pose a problem if the patient was breathing spontaneously, in which case, pressure support ventilation should be used. Air flow should improve once the EB is deployed into a mainstem bronchus.
There are theoretical risks associated with our new technique. Placing the ETT tip distally may increase the risks of carinal injury and endobronchial intubation. Such risks should be minimal if both two- and one-lung ventilations are uncomplicated. The objective is not to press on the carina, but rather leave a small gap between the ETT tip and the carina. It would, therefore, be prudent to check fibrescopically after changes in patient position and whenever any ventilation problems arise. The potential for tracheal injury and for the balloon to shear off also exists. Another theoretical risk is the potential trauma on the tracheal wall when the ETT, pre-loaded with the EB, is passed towards the carina. From Figure 1, one can see that tip of the EB protrudes slightly through the Murphy eye. We recommend that this protrusion should be minimised to the extent that the EB tip is sticking out only enough to not be pushed back into the ETT lumen (Figure 1). We have not evaluated the tracheal wall after surgery in our patients and that has so far been a deficiency of our study. We do not, however, feel that the trauma should be any more than that caused by the blunt tip of the angulated endobronchial stump of a DLT, which is much larger and stiffer.
The bronchial cuff on a DLT is supported securely by a stiff endobronchial stem. In fact, the cuff takes up only a tiny fraction of the endobronchial cross-sectional area. In comparison, the balloon on an Arndt/Coopdech/Fogarty/Cohen EB is supported by a hollow catheter, which occupies only a tiny fraction of the endobronchial diameter. The balloon is anchored 40 to 45 cm away, at the proximal end of the flexible catheter. This weak support perhaps explains the tendency of the EB balloon to move, especially during surgical manipulation of the lungs.
Further studies are required to determine whether our technique is reliable, safe and sufficiently user-friendly. Until then, the DLT remains our preferred device for adult OLA, because of its ease of use, reliability and low cost. Compared to the ETT-EB technique, DLT use is associated with more sore throat and hoarseness, but this rarely lasts beyond 72 hours (11) and serious airway injuries are rare (8-10). The ETT-EB technique should be considered when intubation is difficult, in already intubated patients requiring OLA (e.g. trauma (12,13)), in the presence of distorted tracheobronchial anatomy, when conditions for switching to an ETT after use of a DLT are expected to be poor (e.g. facial oedema) and whenever reduced sore throat and hoarseness (e.g. singers, speakers, reporters) is advantageous.
In summary, we have reported a novel technique for endobronchial balloon placement in adults. It involves the deliberate distal placement of the ETT and deflection of the blocker through the Murphy eye. We have also demonstrated that threading the blocker through the Murphy eye can be done after (for patients already with an ETT [greater than or equal to]8.5 mm ID in situ) or before intubation.
Placing the endotracheal tube tip near the carina and passing the endobronchial blocker through the Murphy eye may reduce the chance of cephalad dislodgement of the blocker during one-lung anaesthesia.
Accepted for publication on May 6, 2009.
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A. M. H. HO *, S. K. NG [[dagger]], K. H. S. TSANG [[double dagger]], S. W. AU [[section]], C. S. H. NG **, L. A. H. CRITCHLEY [[dagger][dagger]], M. K. KARMAKAR [[double dagger][double dagger]]
Departments of Anaesthesia and Intensive Care and Surgery, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, New Territories, Hong Kong SAR
* M.D., F.R.C.P., F.C.C.P., Professor, Department of Anaesthesia and Intensive Care.
[[dagger]] M.B., B.S., F.A.N.Z.C.A., Consultant, Department of Anaesthesia and Intensive Care.
[[double dagger]] M.B., Ch.B., F.A.N.Z.C.A., Associate Consultant, Department of Anaesthesia and Intensive Care.
[[section]] M.B., Medical Officer, Department of Anaesthesia and Intensive Care.
** M.D., F.R.C.S.(Ed), Resident Specialist, Department of Surgery.
[[dagger][dagger]] M.D., F.F.A.R.C.S.I., Professor, Department of Anaesthesia and Intensive Care.
[[double dagger][double dagger]] M.D., F.R.C.A., Associate Professor, Department of Anaesthesia and Intensive Care.
Address for correspondence: Department of Anaesthesia and Intensive Care, Prince of Wales Hospital, Shatin, NT, Hong Kong SAR. Email: email@example.com
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|Author:||Ho, A.M.H.; Ng, S.K.; Tsang, K.H.S.; Au, S.W.; Ng, C.S.H.; Critchley, L.A.H.; Karmakar, M.K.|
|Publication:||Anaesthesia and Intensive Care|
|Date:||Nov 1, 2009|
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